(a) Field of the Invention
A current collector for a flexible electrode, a method of manufacturing the same, and a negative electrode including the same are disclosed.
(b) Description of the Related Art
As portable devices, such as mobile phones, laptop computers, personal digital assistants (PDA), electronic papers, and so forth, are down-sized and become increasingly thinner recently, researchers are paying more attention to down-sizing rechargeable lithium batteries and portability of the rechargeable lithium batteries, which are energy sources of the portable devices.
The rechargeable lithium batteries include: a lithium transition element composite oxide having a layered structure, such as lithium cobalt oxide, as a positive electrode; a graphite-based carbon cleaning agent, a silicon oxide-based composite material, silicon, a tin alloy, lithium, or vanadium oxide as a negative electrode; and a non-aqueous-based liquid and polymer electrolyte, and take advantage of high electric power and electrical capacity that are generated from a reaction where lithium ions intercalate/deintercalate to/from the inside of the active material.
An electrode is generally formed by fixing a powder material, which is used as an active material, on copper foil, which is a current collector, with an organic polymer, which is used as a binder. Usually, a copper plate is used as a current collector.
When a copper plate is used as a current collector, a compression process is performed to increase adherence between an electrode assembly and the current collector. After the compression process, dust is generated, and while the battery is charged and discharged, the negative active material comes off the surface of the current collector.
Since the decrease in the adherence between the negative active material and the copper current collector and an active material delamination phenomenon occurring from the decreased adherence increase the internal resistance of the battery, the performance of the battery is greatly deteriorated, such as deteriorated output characteristics of the battery and decreased battery capacity.
Also, in a flexible rechargeable lithium battery, the entire current collector is bent or deformed and it may be partially delaminated. As a result, the charge-discharge cycle characteristics of the battery are deteriorated and the cycle-life of the battery is reduced.